Gync is currently only for Turing, (and Ampere once it releaes) only, not too sure about Freesync support (if the update has even been rolled out)
LG updated the firmware a few weeks ago to fully enable Freesync Premium support on AMD cards. Works flawlessly, even on older Vega generation cards.
Nvidia appear to have locked down Gsync on these to only RTX and 3000 series cards, in a typical money grabbing move (they can get away with anything as Nvidia's mind share is so massive).